////
/// @group settings/warnings
////

/// Suppressed warnings map
///
/// This map is used to determine which deprecation warnings to **not** show
/// to users when compiling sass. This is in place for codebases that do not
/// have the necessary capacity to upgrade and remove the deprecation,
/// particularly if the deprecation is significant. For example, the removal of
/// mixins and functions that were previously available to users of Frontend.
///
/// You can add to this map and define which warnings to suppress by appending to
/// it using the warning key, found in the warning message. For example:
///
/// @example scss:
///   // warning message:
///   //  $foobar is no longer supported. To silence this warning, update
///   //  $govuk-suppressed-warnings with key: "foobar"
///   $govuk-suppressed-warnings: (
///     foobar
///   );
///
/// @type List
/// @access public

$govuk-suppressed-warnings: () !default;

/// Warnings
///
/// Acts as a wrapper for the built in `@warn` sass function
///
/// We use this instead of using `@warn` for 3 reasons:
///
/// - To check if a warning is being suppressed through `$govuk-suppressed-warnings`,
/// in which case we don't call `@warn` and printing the warning to the user
/// - To format the passed warning `$message` with the warning key at the end
/// - To prevent duplicate warnings by adding the passed `$key` to
/// `$govuk-suppressed-warnings` after `@warn` is called to ensure it only runs
/// once per sass compilation (unless $silence-further-warnings is false)
///
/// @param {String} $key - The key to be checked against `$govuk-suppressed-warnings`
/// and then passed to it to prevent multiple of the same warning.
/// @param {String} $message - The message to use when calling `@warn`
/// @param {Boolean} $silence-further-warnings - Whether to silence future
/// warnings that use the same $key
/// @access private

@mixin _warning($key, $message, $silence-further-warnings: true) {
  @if _should-warn($key) {
    @warn _warning-text($key, $message);

    @if $silence-further-warnings {
      $govuk-suppressed-warnings: append($govuk-suppressed-warnings, $key) !global;
    }
  }
}

/// Check whether a key is present in the suppressed warnings list.
///
/// @param {String} $key - The key to be checked against `$govuk-suppressed-warnings`.
/// @access private

@function _should-warn($key) {
  @return index($govuk-suppressed-warnings, $key) == null;
}

/// Format a warning by appending information on how to suppress it.
///
/// @param {String} $key - The key needed to suppress the warning.
/// @param {String} $message - The warning text.
/// @access private

@function _warning-text($key, $message) {
  @return $message + " To silence this warning, update $govuk-suppressed-warnings " + 'with key: "#{$key}"';
}
